[The mechanism of the fish production in the region of the middle Danube]

Stanković, S.; Janković, D.

Abstract

The present paper deals with the analysis of the fish production mechanism in the unmeliorated flood region of the middle Danube and the Hungarian frontier. The region is subject to periodical floods that take place when water level rises 400 cm above the normal level and usually last from the springtime (March, April) until the middle or exceptionally the end of the summer, i.e. three months in average. During the flood the flooded area forms an immense productive surface (over 32.000 hectars). The organic productivity is expressed trough the fish yield. The latter was followed throughout the periods 1914/1935 and 1945/1967 (graphs 1-3). It was established that the level of the fish yield depends fully on the extent and duration of the flood in days. The fluctuations of the fish yield range roughly between 470.000 kg of the total amount (in 1921, the flood lasted only 20 days) to over 1.560.000 kg (in 1924, the flood lasted 198 days). Besides cases of delayed effect of the flood duration were analysed and the delay could be manifested even a whole year later. Finally the dynamics of the catch of economic species - carp and pike - followed and it is pointed out that fishing of these species should be done under special regulations.